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Publication Abstract from PubMed

The structural basis for the photochromism in the fluorescent protein Dronpa is poorly understood, because the crystal structures of the bright state of the protein did not provide an answer to the mechanism of the photochromism, and structural determination of the dark state has been elusive. We performed NMR analyses of Dronpa in solution at ambient temperatures to find structural flexibility of the protein in the dark state. Light-induced changes in interactions between the chromophore and beta-barrel are responsible for switching between the two states. In the bright state, the apex of the chromophore tethers to the barrel by a hydrogen bond, and an imidazole ring protruding from the barrel stabilizes the plane of the chromophore. These interactions are disrupted by strong illumination with blue light, and the chromophore, together with a part of the beta-barrel, becomes flexible, leading to a nonradiative decay process.

Light-dependent regulation of structural flexibility in a photochromic fluorescent protein.,Mizuno H, Mal TK, Walchli M, Kikuchi A, Fukano T, Ando R, Jeyakanthan J, Taka J, Shiro Y, Ikura M, Miyawaki A Proc Natl Acad Sci U S A. 2008 Jul 8;105(27):9227-32. Epub 2008 Jun 23. PMID:18574155^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.